Rear Crankshaft seal?

I've heard of the inner layer/liner of oil lines becoming separated and essentially blocking the passage of oil, while appearing normal externally. Maybe worth checking the rubber lines for this.

You don't have the tank mounted too high by chance?

The bottom of the tank should be about in line with the bottom of the engine.

Thank you for all of the input.

Rear seal was brand new.

I visually looked at the oil line, looked brand new as well. I will re-inspect the inside. I wonder if i could apply a vacuum to test the inner membrane.

Mark you may be on to something here, the van is park at my friends home and I need to go harvest the oil tank this weekend but from memory it seems as though it was mounted at a higher elevation. Any idea how much above would cause a problem? Is this due to a lack of pressure on the scavenge side?

Any liquid will try to flow to the lowest point via gravity/siphon effect, only thing stopping the oil from flowing to the lowest point is the pump gears and tolerances. If the tank bottom is inline with the sump bottom then gravity doesn't come into play, at least not to as great extent.

Just looked, my 914/6 tank outlet is only about 2" higher than the return tube on the bottom of the cooler. I think you'll find 911 tanks are about the same.

The PO used factory oil lines to connect engine to tank, so the elevation difference was not a issue. Didn’t porsche mount 72 oil tanks higher as well? Would think the scavange side would have to have enough pressure to over come elevations changes when running. I understand that when shut down oil will drain to lowest point.http://forums.pelicanparts.com/uploa...1541189762.jpg
http://forums.pelicanparts.com/uploa...1541189762.jpg

I visual inspected oil line, sure don’t see eveidence of inner lining failing and collapsing.

Back to the potential that the same size springs on the pressure relief valves could have created a issue?????

I can attest to Mark's comment about tank placement relative to engine causing oil to slowly make its way from the tank to the engine when the car isn't running. I have this issue in my racecar, and have to jack up the rear of the car when stored to keep the oil in the front mounted tank. No issues when running though.

I'm going to ask a silly question now - are you sure that the engine was really filling with oil? Granted a leaking seal might be caused by this. Or maybe just it was just a bad seal like wndsnd posted earlier in the thread? Were there other symptoms? The oil level in the tank would be low, for example, if the engine was not scavenging properly. The engine might also be down on power due extreme oil sloshing. Another thing is it would probably smoke like a mother out the exhaust due to oil getting past the piston rings into the combustion chamber.

Scott